1. Field of the Invention
The invention relates generally to an apparatus for treating surfaces of wafer-shaped articles, such as semiconductor wafers.
2. Description of Related Art
Semiconductor wafers are subjected to various surface treatment processes such as etching, cleaning, polishing and material deposition. To accommodate such processes, a single wafer may be supported in relation to one or more treatment fluid nozzles by a chuck associated with a rotatable carrier, as is described for example in U.S. Pat. Nos. 4,903,717 and 5,513,668.
Alternatively, a chuck in the form of a ring rotor adapted to support a wafer may be located within a closed process chamber and driven without physical contact through an active magnetic bearing, as is described for example in U.S. Pat. No. 8,490,634.
For chucks of the type described in U.S. Pat. No. 8,490,634, the chuck body overlies a peripheral region of the wafer, such that for some processes this region cannot be adequately treated. U.S. Pat. No. 5,845,662 discloses a ring-shaped chuck that does not significantly overlap a supported wafer, but a basket-like configuration of pivotable or flexible fingers is required, which keeps the wafer spaced axially apart from the ring-shaped chuck, and increases the size and complexity of the device.